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Publication numberUS20050168585 A1
Publication typeApplication
Application numberUS 11/044,055
Publication dateAug 4, 2005
Filing dateJan 28, 2005
Priority dateJan 30, 2004
Publication number044055, 11044055, US 2005/0168585 A1, US 2005/168585 A1, US 20050168585 A1, US 20050168585A1, US 2005168585 A1, US 2005168585A1, US-A1-20050168585, US-A1-2005168585, US2005/0168585A1, US2005/168585A1, US20050168585 A1, US20050168585A1, US2005168585 A1, US2005168585A1
InventorsYukio Uenaka, Shuzo Seo
Original AssigneePentax Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Anti-shake apparatus
US 20050168585 A1
Abstract
An anti-shake apparatus of a photographing-apparatus comprises a movable-unit and a fixed-unit. The movable-unit has an imaging-device, a position-detecting magnetic-field generating unit. The movable-unit can be moved in a first-direction and a second-direction. The fixed-unit has a hall-element unit. The first-direction is perpendicular to an optical axis of a camera-lens of the photographing-apparatus. The second-direction is perpendicular to the optical axis and the first-direction. The position-detecting magnetic-field generating unit is used for detecting a first location in the first-direction of the movable-unit, and a second location in the second-direction of the movable-unit, and has a position-detecting coil. The hall-element unit has a horizontal hall-element which is used for detecting the first location, and has a vertical hall-element which is used for detecting the second location. The position-detecting coil is magnetized by being electrified only when detecting the first location and the second location, and faces the hall-element unit.
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Claims(11)
1. An anti-shake apparatus of a photographing apparatus, comprising:
a movable unit that has one of an imaging device and a hand-shake correcting lens, and has a position-detecting magnetic-field generating unit, and is movable in a first direction and a second direction; and
a fixed unit that has a magnetic-field change-detecting unit;
said first direction being perpendicular to an optical axis of a camera lens of said photographing apparatus;
said second direction being perpendicular to said optical axis and said first direction;
said position-detecting magnetic-field generating unit being used for detecting a first location in said first direction of said movable unit, and a second location in said second direction of said movable unit, and having a position-detecting coil;
said magnetic-field change-detecting unit having a horizontal magnetic-field change-detecting element which is used for detecting said first location, and having a vertical magnetic-field change-detecting element which is used for detecting said second location; and
said position-detecting coil being magnetized by being electrified only when detecting said first location and said second location, and said position-detecting coil facing said magnetic-field change detecting unit.
2. The anti-shake apparatus according to claim 1, wherein said position-detecting coil is wound, such that its outer circumference shape, viewed from a third direction which is parallel to said optical axis, is a square and faces said magnetic-field change-detecting unit; and
an external structure of said square forms lines which are parallel to one of said first direction and said second direction.
3. The anti-shake apparatus according to claim 2, wherein said movable unit is located at the center of its movement range, in both said first and second directions, when the center area of one of said imaging device and said hand-shake correcting lens which is included in said movable unit, is located on said optical axis.
4. The anti-shake apparatus according to claim 3, wherein said magnetic-field change-detecting unit has first and second horizontal magnetic-field change-detecting elements as said horizontal magnetic-field change-detecting element, and first and second vertical magnetic-field change-detecting elements as said vertical magnetic-field change-detecting element; and
when the center of one of said imaging device and said hand-shake correcting lens which is included in said movable unit passes through said optical axis, said first horizontal magnetic-field change-detecting element is located at a place which faces midway along a side of said square outer circumference, in said second direction, of said position-detecting coil; said second horizontal magnetic-field change-detecting element is located at a place which faces midway along another side of said square outer circumference, in said second direction, of said position-detecting coil; said first vertical magnetic-field change-detecting element is located at a place which faces midway along a side of said square outer circumference, in said first direction, of said position-detecting coil; and said second vertical magnetic-field change-detecting element is located at a place which faces midway along another side of said square outer circumference, in said first direction, of said position-detecting coil.
5. The anti-shake apparatus according to claim 4, wherein said magnetic-field change-detecting unit is a two-axes hall element;
said first and second horizontal magnetic-field change-detecting elements are hall elements; and
said first and second vertical magnetic-field change-detecting elements are hall elements.
6. The anti-shake apparatus according to claim 1, wherein said position-detecting coil is magnetized where a N pole and a S pole are arranged in a third direction which is parallel to said optical axis.
7. The anti-shake apparatus according to claim 1, wherein said position-detecting coil is used for generating a magnetic-field.
8. The anti-shake apparatus according to claim 1, wherein said position-detecting magnetic-field generating unit has a magnetic core;
said position-detecting coil is wound around said magnetic core;
said magnetic core is made of a magnetic material, and has a rectangular prism form; and
said rectangular prism form has a front-surface which faces said magnetic-field change-detecting unit and is a square shape that is the same as said outer circumference of said position-detecting coil.
9. The anti-shake apparatus according to claim 1, wherein said position-detecting coil forms a seat and a spiral shape coil pattern.
10. The anti-shake apparatus according to claim 1, wherein said fixed unit has a position-detecting yoke;
said position-detecting yoke is attached to a back surface side of said fixed unit, which is the opposite side to the surface having said magnetic-field change-detecting unit, and is made of a magnetic material.
11. The anti-shake apparatus according to claim 1, wherein said horizontal magnetic-field change-detecting element and said vertical magnetic-field change-detecting element are one of hall elements, MI sensors, magnetic resonance-type magnetic-field detecting elements, and MR elements.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an anti-shake apparatus for a photographing device (apparatus), and in particular to a position-detecting apparatus for a movable unit that includes the imaging device etc., and that can be moved for correcting the hand-shake effect.

2. Description of the Related Art

An anti-shake apparatus for a photographing apparatus is proposed. The anti-shake apparatus corrects for the hand-shake effect by moving a hand-shake correcting lens or the imaging device on a plane that is perpendicular to the optical axis, corresponding to the amount of hand-shake which occurs during imaging.

Japanese unexamined patent publication (KOKAI) No. 2002-229090 discloses an anti-shake apparatus for a photographing apparatus. The anti-shake apparatus performs a moving operation of a movable unit, which includes a hand-shake correcting lens, by using a permanent magnet and a coil, and a position-detecting operation of the movable unit, by using a hall element and a permanent magnet.

However, this anti-shake apparatus has two magnets. One of the two magnets (a first magnet) is used for driving (moving) the movable unit in a first direction which is perpendicular to the optical axis of the photographing apparatus, and for detecting a first location in the first direction of the movable unit. The other magnet (a second magnet) is used for driving (moving) the movable unit in a second direction which is perpendicular to the optical axis and the first direction, and for detecting a second location in the second direction of the movable unit.

This anti-shake apparatus has two driving coils and two hall elements. One of the two driving coils (a first driving coil) is used for driving the movable unit in the first direction. The other driving coil (a second driving coil) is used for driving the movable unit in the second direction. One of the two hall elements (a first hall element) is used for detecting the first location in the first direction of the movable unit. The other hall element (a second hall element) is used for detecting the second location in the second direction of the movable unit.

The first driving coil and the first hall element are arranged in the second direction, and face the first magnet. The second driving coil and the second hall element are arranged in the first direction, and face the second magnet.

Because the first and second magnets are permanent magnets, an attracting force occurs between the magnet and the hall element for detecting the position of the movable unit, so that this attracting force becomes a resistance force for driving the movable unit.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an apparatus which reduces the resistance force on the basis of the attracting force which occurs based on the magnetic-field for detecting the position of the movable unit in the anti-shake apparatus, while driving the movable unit.

According to the present invention, an anti-shake apparatus of a photographing apparatus comprises a movable unit and a fixed unit.

The movable unit has one of an imaging device and a hand-shake correcting lens, and has a position-detecting magnetic-field generating unit, and can be moved in a first direction and a second direction.

The fixed unit has a magnetic-field change-detecting unit.

The first direction is perpendicular to an optical axis of a camera lens of the photographing apparatus.

The second direction is perpendicular to the optical axis and the first direction.

The position-detecting magnetic-field generating unit is used for detecting a first location in the first direction of the movable unit, and a second location in the second direction of the movable unit, and has a position-detecting coil.

The magnetic-field change-detecting unit has a horizontal magnetic-filed change-detecting element which is used for detecting the first location in the first direction of the movable unit, and has a vertical magnetic-field change-detecting element which is used for detecting the second location in the second direction of the movable unit.

The position-detecting coil is magnetized by being electrified only when detecting the first location in the first direction of the movable unit and the second location in the second direction of the movable unit, and the position-detecting coil faces the magnetic-field change detecting unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will be better understood from the following description, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a photographing apparatus of the embodiment viewed from the back side of the photographing apparatus;

FIG. 2 is a front view of the photographing apparatus;

FIG. 3 is a circuit construction diagram of the photographing apparatus;

FIG. 4 is a figure showing the construction of the anti-shake apparatus;

FIG. 5 is a view along line A-A of FIG. 4;

FIG. 6 is a view along line B-B of FIG. 4;

FIG. 7 is a perspective view of the hall element unit and the position-detecting magnetic-field generating unit in the first embodiment;

FIG. 8 is a circuit construction diagram of the part of the circuit for detecting the first location in the first direction of the movable unit, with the hall element unit and the hall-element signal-processing circuit;

FIG. 9 is a circuit construction diagram of the part of the circuit for detecting the second location in the second direction of the movable unit, with the hall element unit and the hall-element signal-processing circuit;

FIG. 10 is a view along line A-A of FIG. 4, when the magnetic-field generating apparatus of the magnetic-field generating unit is made of a permanent magnet (not in this invention, just example);

FIG. 11 is a view along line A-A of FIG. 4, when the movable unit is moved in the second direction from the state shown in FIG. 10 (not in this invention, just example);

FIG. 12 is a view along line A-A of FIG. 4, where there is no attracting force;

FIG. 13 is a flowchart of the anti-shake operation, which is performed at every predetermined time interval, as an interruption process;

FIG. 14 is a perspective view of the hall element unit and the position-detecting magnetic-field generating unit in the second embodiment; and

FIG. 15 is a perspective view of the hall element unit and the position-detecting magnetic-field generating unit in the third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described below with reference to the first embodiment shown in the FIGS. 1˜13. In this embodiment, the photographing device 1 is a digital camera. The photographing device 1 has an optical axis LX.

In order to explain the direction in this embodiment, a first direction x, a second direction y, and a third direction z are defined (see FIG. 1). The first direction x is a horizontal direction which is perpendicular to the optical axis LX. The second direction y is a vertical direction which is perpendicular to the optical axis LX and the first direction x. The third direction z is a horizontal direction which is parallel to the optical axis LX and perpendicular to both the first direction x and the second direction y.

FIG. 5 shows a construction diagram of the section along line A-A of FIG. 4. FIG. 6 shows a construction diagram of the section along line B-B of FIG. 4.

The imaging part of the photographing apparatus 1 comprises a Pon button 11, a Pon switch 11 a, a photometric switch 12 a, a release button 13, a release switch 13 a, a CPU 21, an imaging block 22, an AE (automatic exposure) unit 23, an AF (automatic focusing) unit 24, an imaging unit 39 a in the anti-shake apparatus 30, and a camera lens 67 (see FIGS. 1, 2, and 3).

Whether the Pon switch 11 a is in the on state or the off state, is determined by a state of the Pon button 11, so that the ON/OFF states of the photographing apparatus 1 are changed corresponding to the ON/OFF states of the Pon switch 11 a.

The photographic subject image is taken as an optical image through the camera lens 67 by the imaging block 22, which drives the imaging unit 39 a, so that the image, which is taken, is indicated on the LCD monitor 17. The photographic subject image can be optically observed by the optical finder (not depicted).

When the release button 13 is half pushed by the operator, the photometric switch 12 a changes to the on state, so that the photometric operation, the AF sensing operation, and the focusing operation are performed.

When the release button 13 is fully pushed by the operator, the release switch 13 a changes to the on state, so that the imaging operation is performed, and the image, which is taken, is stored.

The imaging block 22 drives the imaging unit 39 a. The AE unit 23 performs the photometric operation for the photographic subject, calculates the photometric values, and calculates the aperture value and the time length of the exposure time, which is needed for imaging, corresponding to the photometric values. The AF unit 24 performs the AF sensing operation, and performs the focusing operation, which is needed for the imaging, corresponding to the result of the AF sensing operation. In the focusing operation, the position of the camera lens 67 is moved in the optical axis LX direction.

The anti-shaking part of the photographing apparatus 1 comprises an anti-shake button 14, an anti-shake switch 14 a, a CPU 21, an angular velocity detecting unit 25, a first driver circuit 29, an anti-shake apparatus 30, a hall-element signal-processing circuit 45, a second driver circuit 48, and the camera lens 67.

When the anti-shake button 14 is fully pushed by the operator, the anti-shake switch 14 a changes to the on state, so that the anti-shake operation is performed where the angular velocity detecting unit 25 and the anti-shake apparatus 30 are driven, at every predetermined time interval, independently of the other operations which include the photometric operation etc. When the anti-shake switch 14 a is in the on state, in other words in the anti-shake mode, the parameter IS is set to 1 (IS=1). When the anti-shake switch 14 a is not in the on state, in other words in the non anti-shake mode, the parameter IS is set to 0 (IS=0). In the first embodiment, the predetermined time interval is 1 ms.

The various output commands corresponding to the input signals of these switches are controlled by the CPU 21.

The information regarding whether the photometric switch 12 a is in the on state or in the off state, is input to port P12 of the CPU 21 as a 1-bit digital signal. The information regarding whether the release switch 13 a is in the on state or in the off state, is input to port P13 of the CPU 21 as a 1-bit digital signal. The information regarding whether the anti-shake switch 14 a is in the on state or in the off state, is input to port P14 of the CPU 21 as a 1-bit digital signal.

The imaging block 22 is connected to port P3 of the CPU 21 for inputting and outputting signals. The AE unit 23 is connected to port P4 of the CPU 21 for inputting and outputting signals. The AF unit 24 is connected to port P5 of the CPU 21 for inputting and outputting signals.

Next, the details of the input and output relationship with the CPU 21 for the angular velocity unit 25, the first driver circuit 29, the anti-shake apparatus 30, the hall-element signal-processing circuit 45, and the second driver circuit 48 are explained.

The angular velocity unit 25 has a first angular velocity sensor 26, a second angular velocity sensor 27, and a combined amplifier and high-pass filter circuit 28. The first angular velocity sensor 26 detects the velocity-component in the first direction x of the angular velocity of the photographing apparatus 1, at every predetermined time interval (1 ms). The second angular velocity sensor 27 detects the velocity-component in the second direction y of the angular velocity of the photographing apparatus 1, at every predetermined time interval (1 ms).

The combined amplifier and high-pass filter circuit 28 amplifies the signal regarding the first direction x of the angular velocity (the velocity-component in the first direction x of the angular velocity), reduces a null voltage and a panning of the first angular velocity sensor 26, and outputs the analogue signal to the A/D converter A/D 0 of the CPU 21 as a first angular velocity vx.

The combined amplifier and high-pass filter circuit 28 amplifies the signal regarding the second direction y of the angular velocity (the velocity-component in the second direction y of the angular velocity), reduces a null voltage and a panning of the second angular velocity sensor 27, and outputs the analogue signal to the A/D converter A/D 1 of the CPU 21 as a second angular velocity vy.

The CPU 21 converts the first angular velocity vx which is input to the A/D converter A/D 0 and the second angular velocity vy which is input to the A/D converter A/D 1 to the digital signals (A/D converting operation), and calculates the hand-shake quantity, which occurs in the predetermined time (1 ms), on the basis of the converted digital signals and the converting coefficient, where focal distance is considered. Accordingly, the CPU 21 and the angular velocity detecting unit 25 have a function which calculates the hand-shake quantity.

The CPU 21 calculates the position S of the imaging unit 39 a (the movable unit 30 a), which should be moved, corresponding to the hand-shake quantity which is calculated, for the first direction x and the second direction y. The location in the first direction x of the position S is defined as sx, and the location in the second direction y of the position S is defined as sy. The movement of the movable unit 30 a, which includes the imaging unit 39 a, is performed by using electro-magnetic force and is described later. The driving force D, which drives the first driver circuit 29 in order to move the movable unit 30 a to the position S, has a first PWM duty dx as the driving-force component in the first direction x and a second PWM duty dy as the driving-force component in the second direction y.

The anti-shake apparatus 30 is an apparatus which corrects the hand-shake effect, by moving the imaging unit 39 a to the position S, by canceling lag of the photographic subject image on the imaging surface of the imaging device 39 a 1, and by stabilizing the photographing subject image that reaches the imaging surface of the imaging device 39 a 1.

The anti-shake apparatus 30 has a movable unit 30 a, which includes the imaging unit 39 a, and a fixed unit 30 b. Or, the anti-shake apparatus 30 is composed of a driving part which moves the movable unit 30 a by electro-magnetic force to the position S, and a position-detecting part which detects the position of the movable unit 30 a (a detected-position P).

The size and the direction of the electro-magnetic force are determined by the size and the direction of the current which flows in the coil, and the size and the direction of the magnetic-field of the magnet.

The driving of the movable unit 30 a of the anti-shake apparatus 30, is performed by the first driver circuit 29 which has the first PWM duty dx input from the PWM 0 of the CPU 21 and has the second PWM duty dy input from the PWM 1 of the CPU 21. The detected-position P of the movable unit 30 a, either before moving or after moving, which is moved by driving the first driver circuit 29, is detected by the hall element unit 44 b and the hall-element signal-processing circuit 45.

Information of a first location in the first direction x for the detected-position P, in other words a first detected-position signal px is input to the A/D converter A/D 2 of the CPU 21. The first detected-position signal px is an analogue signal, and is converted to a digital signal through the A/D converter A/D 2 (A/D converting operation). The first location in the first direction x for the detected-position P, after the A/D converting operation, is defined as pdx, corresponding to the first detected-position signal px.

Information of a second location in the second direction y for the detected-position P, in other words a second detected-position signal py is input to the A/D converter A/D 3 of the CPU 21. The second detected-position signal py is an analogue signal, and is converted to a digital signal through the A/D converter A/D 3 (A/D converting operation). The second location in the second direction y for the detected-position P, after the A/D converting operation, is defined as pdy, corresponding to the second detected-position signal py.

The PID (Proportional Integral Differential) control is performed on the basis of the data for the detected-position P (pdx, pdy) and the data for the position S (sx, sy) which should be moved to.

The movable unit 30 a has a first driving coil 31 a, a second driving coil 32 a, an imaging unit 39 a, a position-detecting magnetic-field generating unit 41 a, a movable circuit board 49 a, a shaft for movement 50 a, a first bearing unit for horizontal movement 51 a, a second bearing unit for horizontal movement 52 a, a third bearing unit for horizontal movement 53 a, and a plate 64 a (see FIGS. 4, 5, and 6).

The fixed unit 30 b has a first permanent driving magnet 33 b, a second permanent driving magnet 34 b, a first driving yoke 35 b, a second driving yoke 36 b, a position-detecting yoke 43 b, a hall element unit 44 b, a first bearing unit for vertical movement 54 b, a second bearing unit for vertical movement 55 b, a third bearing unit for vertical movement 56 b, a fourth bearing unit for vertical movement 57 b, and a base board 65 b.

The shaft for movement 50 a of the movable unit 30 a has a channel shape when viewed from the third direction z. The first, second, third, and fourth bearing units for vertical movement 54 b, 55 b, 56 b, and 57 b are attached to the base board 65 b of the fixed unit 30 b. The shaft for movement 50 a is slidably supported in the vertical direction (the second direction y), by the first, second, third, and fourth bearing units for vertical movement 54 b, 55 b, 56 b, and 57 b.

The first and second bearing units for vertical movement 54 b and 55 b have slots which extend in the second direction y.

Therefore, the movable unit 30 a can move relative to the fixed unit 30 b, in the vertical direction (the second direction y).

The shaft for movement 50 a is slidably supported in the horizontal direction (the first direction x), by the first, second, and third bearing units for horizontal movement 51 a, 52 a, and 53 a of the movable unit 30 a. Therefore, the movable unit 30 a, except for the shaft for movement 50 a, can move relative to the fixed unit 30 b and the shaft for movement 50 a, in the horizontal direction (the first direction x).

When the center area of the imaging device 39 a 1 is located on the optical axis LX of the camera lens 67, the location relation between the movable unit 30 a and the fixed unit 30 b is set up so that the movable unit 30 a is located at the center of its movement range in both the first direction x and the second direction y, in order to utilize the full size of the imaging range of the imaging device 39 a 1.

A rectangle shape, which forms the imaging surface of the imaging device 39 a 1, has two diagonal lines. In this embodiment, the center of the imaging device 39 a 1 is the crossing point of these two diagonal lines.

The imaging unit 39 a, the plate 64 a, and the movable circuit board 49 a are attached, in this order along the optical axis LX direction, viewed from the side of the camera lens 67. The imaging unit 39 a has an imaging device 39 a 1 (such as a CCD or a CMOS etc.), a stage 39 a 2, a holding unit 39 a 3, and an optical low-pass filter 39 a 4. The stage 39 a 2 and the plate 64 a hold and urge the imaging device 39 a 1, the holding unit 39 a 3, and the optical low-pass filter 39 a 4 in the optical axis LX direction.

The first, second, and third bearing units for horizontal movement 51 a, 52 a, and 53 a are attached to the stage 39 a 2. The imaging device 39 a 1 is attached to the plate 64 a, so that positioning of the imaging device 39 a 1 is performed where the imaging device 39 a 1 is perpendicular to the optical axis LX of the camera lens 67. In the case where the plate 64 a is made of a metallic material, the plate 64 a has the effect of radiating heat from the imaging device 39 a 1, by contacting the imaging device 39 a 1.

The first driving coil 31 a, the second driving coil 32 a, and the position-detecting magnetic-field generating unit 41 a are attached to the movable circuit board 49 a.

The first driving coil 31 a forms a seat and a spiral shape coil pattern. The coil pattern of the first driving coil 31 a has lines which are parallel to either the first direction x or the second direction y, where the movable unit 30 a which includes the first driving coil 31 a, is moved in the first direction x, by a first electro-magnetic force. The lines which are parallel to the second direction y, are used for moving the movable unit 30 a in the first direction x. The lines which are parallel to the second direction y, have a first effective length L1.

The first electro-magnetic force occurs on the basis of the current direction of the first driving coil 31 a and the magnetic-field direction of the first permanent driving magnet 33 b.

The second driving coil 32 a forms a seat and a spiral shape coil pattern. The coil pattern of the second driving coil 32 a has lines which are parallel to either the first direction x or the second direction y, where the movable unit 30 a which includes the second driving coil 32 a, is moved in the second direction y, by a second electro-magnetic force. The lines which are parallel to the first direction x, are used for moving the movable unit 30 a in the second direction y. The lines which are parallel to the first direction x, have a second effective length L2.

The second electromagnetic force occurs on the basis of the current direction of the second driving coil 32 a and the magnetic-field direction of the second permanent driving magnet 34 b.

In the first embodiment, the first driving coil 31 a is attached to the right edge area of the movable circuit board 49 a (one of the edge areas of the movable circuit board 49 a in the first direction x), viewed from the third direction z and the opposite side of the camera lens 67.

Similarly, the second driving coil 32 a is attached to the upper area of the movable circuit board 49 a (one of the edge areas of the movable circuit board 49 a in the second direction y), viewed from the third direction z and the opposite side of the camera lens 67.

Further, the position-detecting magnetic-field generating unit 41 a is attached to the left edge area of the movable circuit board 49 a (another of the edge areas of the movable circuit board 49 a in the first direction x), viewed from the third direction z and the opposite side of the camera lens 67.

The imaging device 39 a 1 is attached to the middle area of the movable circuit board 49 a between the first driving coil 31 a and the position-detecting magnetic-field generating unit 41 a, in the first direction x.

The first and second driving coils 31 a and 32 a, the imaging device 39 a 1, and the position-detecting magnetic-field generating unit 41 a, are attached on the same side of the movable circuit board 49 a.

The first and second driving coils 31 a and 32 a are connected with the first driver circuit 29 which drives the first and second driving coils 31 a and 32 a through the flexible circuit board (not depicted). The first PWM duty dx is input to the first driver circuit 29 from the PWM 0 of the CPU 21, and the second PWM duty dy is input to the first driver circuit 29 from the PWM 1 of the CPU 21. The first driver circuit 29 supplies power to the first driving coil 31 a corresponding to the value of the first PWM duty dx, and to the second driving coil 32 a corresponding to the value of the second PWM duty dy, to drive the movable unit 30 a.

The position-detecting magnetic-field generating unit 41 a is used for detecting the first location in the first direction x of the movable unit 30 a and the second location in the second direction y of the movable unit 30 a.

The position-detecting magnetic-field generating unit 41 a has a position-detecting coil 41 a 1 as a magnetic-field generating apparatus. The position-detecting coil 41 a 1 is wound, such that its outer circumference shape, viewed from the third direction z, is a square and faces the hall element unit 44 b. The external structure of the square forms lines which are parallel to one of the first direction x and the second direction y (see FIG. 7). The N pole and S pole of the position-detecting coil 41 a 1 are magnetized in the third direction z, when the position-detecting coil 41 a 1 is electrified.

The position-detecting coil 41 a 1 is attached to the movable circuit board 49 a. The movable circuit board 49 a, which is attached to the position-detecting coil 41 a 1, is not depicted in FIG. 7.

Because the outer circumference shape of the winding of the position-detecting coil 41 a 1, which faces the fixed unit 30 b, is square shaped, detecting the position of the movable unit 30 a in the first direction x is not influenced by movement of the movable unit 30 a in the second direction y. Further, detecting the position of the movable unit 30 a in the second direction y is not influenced by movement of the movable unit 30 a in the first direction x.

The position-detecting coil 41 a 1 is electrified, only when position detecting of the movable unit 30 a is performed, so that the position-detecting coil 41 a 1 is not electrified, when position detecting of the movable unit 30 a is not performed.

The position-detecting coil 41 a 1 is connected with the second driver circuit 48, which drives the position-detecting coil 41 a 1, through the flexible circuit board (not depicted). The second driver circuit 48 determines the supply of electricity to the position-detecting coil 41 a 1, on the basis of the on state of the signal output from the port P50 of the CPU 21, and stops the supply of electricity to the position-detecting coil 41 a 1, on the basis of the off state of the signal output from the port P50 of the CPU 21.

Specifically, when the on state signal is output from the port P50 of the CPU 21 to the second driver circuit 48 to perform the position detecting operation for the movable unit 30 a, the position-detecting coil 41 a 1 is electrified (driven), so that the position detecting operation is started.

When the off state signal is output from the port P50 of the CPU 21 to the second driver circuit 48, the position-detecting coil 41 a 1 is not electrified (driven), so that the position detecting operation is stopped.

The control of the ON/OFF states of the position-detecting coil 41 a 1 by the CPU 21 is performed, independently of the moving operation of the movable unit 30 a.

The first permanent driving magnet 33 b is attached to the movable unit side of the fixed unit 30 b, where the first permanent driving magnet 33 b faces the first driving coil 31 a in the third direction z.

The second permanent driving magnet 34 b is attached to the movable unit side of the fixed unit 30 b, where the second permanent driving magnet 34 b faces the second driving coil 32 a in the third direction z.

The hall element unit 44 b is attached to the movable unit side of the fixed unit 30 b, where the hall element unit 44 b faces the position-detecting magnetic-field generating unit 41 a.

The position-detecting yoke 43 b is attached to a back surface side of the fixed unit 30 b, which is the opposite side to the surface having the hall element unit 44 b. The position-detecting yoke 43 b is made of a magnetic material, and raises the magnetic-flux density between the position-detecting magnetic-field generating unit 41 a and the hall element unit 44 b.

The first permanent driving magnet 33 b is attached to the first driving yoke 35 b, under the condition where N pole and S pole are arranged in the first direction x. The first driving yoke 35 b is attached to the base board 65 b of the fixed unit 30 b, on the side of the movable unit 30 a, in the third direction z.

The length of the first permanent driving magnet 33 b in the second direction y, is longer in comparison with the first effective length L1 of the first driving coil 31 a. The magnetic-field which influences the first driving coil 31 a, is not changed during movement of the movable unit 30 a in the second direction y.

The second permanent driving magnet 34 b is attached to the second driving yoke 36 b, under the condition where N pole and S pole are arranged in the second direction y. The second driving yoke 36 b is attached to the base board 65 b of the fixed unit 30 b, on the side of the movable unit 30 a, in the third direction z.

The length of the second permanent driving magnet 34 b in the first direction x, is longer in comparison with the second effective length L2 of the second driving coil 32 a. The magnetic-field which influences the second driving coil 32 a, is not changed during movement of the movable unit 30 a in the first direction x.

The first driving yoke 35 b is made of a soft magnetic material, and forms a square-u-shaped channel when viewed from the second direction y. The first permanent driving magnet 33 b and the first driving coil 31 a are inside the channel of the first driving yoke 35 b.

The side of the first driving yoke 35 b, which contacts the first permanent driving magnet 33 b, prevents the magnetic-field of the first permanent driving magnet 33 b from leaking to the surroundings.

The other side of the first driving yoke 35 b, which faces the first permanent driving magnet 33 b, the first driving coil 31 a, and the movable circuit board 49 a, raises the magnetic-flux density between the first permanent driving magnet 33 b and the first driving coil 31 a.

The second driving yoke 36 b is made of a soft magnetic material, and forms a square-u-shaped channel when viewed from the first direction x. The second permanent driving magnet 34 b and the second driving coil 32 a are inside the channel of the second driving yoke 36 b.

The side of the second driving yoke 36 b, which contacts the second permanent driving magnet 34 b, prevents the magnetic-field of the second permanent driving magnet 34 b from leaking to the surroundings.

The other side of the second driving yoke 36 b, which faces the second permanent driving magnet 34 b, the second driving coil 32 a, and the movable circuit board 49 a, raises the magnetic-flux density between the second permanent driving magnet 34 b and the second driving coil 32 a.

The hall element unit 44 b is a two-axes hall element which has four hall elements that are magnetoelectric converting elements (magnetic-field change-detecting elements) using the hall effect (see FIG. 7). The hall element unit 44 b detects the first detected-position signal px, which is used for specifying the first location in the first direction x for the present position P of the movable unit 30 a, and the second detected-position signal py, which is used for specifying the second location in the second direction y for the present position P of the movable unit 30 a.

Two of the four hall elements are a first horizontal hall element hh1 and a second horizontal hall element hh2 for detecting the first location in the first direction x, so that the others are a first vertical hall element hv1 and a second vertical hall element hv2 for detecting the second location in the second direction y.

An input terminal of the first horizontal hall element hh1 and an input terminal of the second horizontal hall element hh2 are connected in series, in order to detect the first location in the first direction x of the movable unit 30 a. The first horizontal hall element hh1 and the second horizontal hall element hh2 are attached to the base board 65 b of the fixed unit 30 b, under the condition where the first horizontal hall element hh1 and the second horizontal hall element hh2 face the position-detecting magnetic-field generating unit 41 a of the movable unit 30 a, in the third direction z.

When the center of the imaging device 39 a 1, passes through the optical axis LX (see FIG. 9), it is desirable that the first horizontal hall element hh1 is located at a place on the hall element unit 44 b which faces midway along a side of the square outer circumference, in the second direction y, of the position-detecting coil 41 a 1, the second horizontal hall element hh2 is located at a place on the hall element unit 44 b which faces midway along the other side of the square outer circumference, in the second direction y, of the position-detecting 41 a 1 (the square outer circumference facing the hall element unit 44 b, viewed from the third direction z), to perform the position-detecting operation utilizing the full size of the square outer circumference of the position-detecting 41 a 1.

An input terminal of the first vertical hall element hv1 and an input terminal of the second vertical hall element hv2 are connected in series, in order to detect the second location in the second direction y of the movable unit 30 a. The first vertical hall element hv1 and the second vertical hall element hv2 are attached to the base board 65 b of the fixed unit 30 b, under the condition where the first vertical hall element hv1 and the second vertical hall element hv2 face the position-detecting magnetic-field generating unit 41 a of the movable unit 30 a, in the third direction z.

When the center of the imaging device 39 a 1, passes through the optical axis LX, it is desirable that the first vertical hall element hv1 is located at a place on the hall element unit 44 b which faces midway along a side of the square outer circumference, in the first direction x, of the position-detecting coil 41 a 1, the second vertical hall element hv2 is located at a place on the hall element unit 44 b which faces midway along the other side of the square outer circumference, in the first direction x, of the position-detecting coil 41 a 1 (the square outer circumference facing the hall element unit 44 b, viewed from the third direction z), to perform the position-detecting operation utilizing the full size of the square outer circumference of the position-detecting coil 41 a 1.

The base board 65 b is a plate state member which becomes the base for attaching the hall element unit 44 b etc., and is arranged being parallel to the imaging surface of the imaging device 39 a 1.

In this embodiment, the base board 65 b is arranged at the side nearer to the camera lens 67 in comparison with the movable circuit board 49 a, in the third direction z. However, the movable circuit board 49 a may be arranged at the side nearer to the camera lens 67 in comparison with the base board 65 b. In this case, the first and second driving coils 31 a and 32 a and the position-detecting magnetic-field generating unit 41 a are arranged on the opposite side of the movable circuit board 49 a to the camera lens 67, so that the first and second permanent driving magnets 33 b and 34 b and the hall element unit 44 b are arranged on the same side of the base board 65 b as the camera lens 67.

The hall-element signal-processing circuit 45 detects a first horizontal potential-difference x1 between output terminals of the first horizontal hall element hh1, based on an output signal of the first horizontal hall element hh1.

The hall-element signal-processing circuit 45 detects a second horizontal potential-difference x2 between output terminals of the second horizontal hall element hh2, based on an output signal of the second horizontal hall element hh2.

The hall-element signal-processing circuit 45 outputs the first detected-position signal px, which specifies the first location in the first direction x of the movable unit 30 a, to the A/D converter A/D 2 of the CPU 21, on the basis of the first and second horizontal potential-differences x1 and x2.

The hall-element signal-processing circuit 45 detects a first vertical potential-difference y1 between output terminals of the first vertical hall element hv1, based on an output signal of the first vertical hall element hv1.

The hall-element signal-processing circuit 45 detects a second vertical potential-difference y2 between output terminals of the second vertical hall element hv2, based on an output signal of the second vertical hall element hv2.

The hall-element signal-processing circuit 45 outputs the second detected-position signal py, which specifies the second location in the second direction y of the movable unit 30 a, to the A/D converter A/D 3 of the CPU 21, on the basis of the first and second vertical potential-differences y1 and y2.

The circuit construction regarding input/output signals of the first and second horizontal hall elements hh1 and hh2, in the hall-element signal-processing circuit 45 is explained using FIG. 8. The circuit construction regarding the first and second vertical hall elements hv1 and hv2 are omitted in FIG. 8, in order to simplify the explanation.

The circuit construction regarding input/output signals of the first and second vertical hall elements hv1 and hv2, in the hall-element signal-processing circuit 45 is explained using FIG. 9. The circuit construction regarding the first and second horizontal hall elements hh1 and hh2 are omitted in FIG. 9, in order to simplify the explanation.

The hall-element signal-processing circuit 45 has a circuit 451, a circuit 452, a circuit 453, a circuit 454, and a circuit 455, for controlling the output of the first and second horizontal hall elements hh1 and hh2, and has a circuit 456, for controlling the input of the first and second horizontal hall elements hh1 and hh2.

The hall-element signal-processing circuit 45 has a circuit 461, a circuit 462, a circuit 463, a circuit 464, and a circuit 466, for controlling the output of the first and second vertical hall elements hv1 and hv2, and has a circuit 466, for controlling the input of the first and second vertical hall elements hv1 and hv2.

Both output terminals of the first horizontal hall element hh1 are connected with the circuit 451, so that the circuit 451 is connected with the circuit 453.

Both output terminals of the second horizontal hall element hh2 are connected with the circuit 452, so that the circuit 452 is connected with the circuit 454.

The circuits 453 and 454 are connected with the circuit 455.

The circuit 451 is a differential amplifier circuit which amplifies the signal difference between the output terminals of the first horizontal hall element hh1, so that the circuit 452 is a differential amplifier circuit which amplifies the signal difference between the output terminals of the second horizontal hall element hh2.

The circuit 453 is a subtracting circuit which calculates the first horizontal potential-difference x1 on the basis of the difference between the amplified signal difference from the circuit 451 and a reference voltage Vref.

The circuit 454 is a subtracting circuit which calculates the second horizontal potential-difference x2 on the basis of the difference between the amplified signal difference from the circuit 452 and the reference voltage Vref.

The circuit 455 is a subtracting circuit which calculates the first detected-position signal px by multiplying a predetermined amplification rate by the difference between the first horizontal potential-difference x1 and the second horizontal potential-difference x2.

The circuit 451 has a resistor R1, a resistor R2, a resistor R3, an operational amplifier A1, and an operational amplifier A2. The operational amplifier A1 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The operational amplifier A2 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

One of the output terminals of the first horizontal hall element hh1 is connected with the non-inverting input terminal of the operational amplifier A1, so that the other terminal of the first horizontal hall element hh1 is connected with the non-inverting input terminal of the operational amplifier A2.

The inverting input terminal of the operational amplifier A1 is connected with the resistors R1 and R2, so that the inverting input terminal of the operational amplifier A2 is connected with the resistors R1 and R3.

The output terminal of the operational amplifier A1 is connected with the resistor R2 and the resistor R7 in the circuit 453. The output terminal of the operational amplifier A2 is connected with the resistor R3 and the resistor R9 in the circuit 453.

The circuit 452 has a resistor R4, a resistor R2, a resistor R6, an operational amplifier A3, and an operational amplifier A4. The operational amplifier A3 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The operational amplifier A4 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

One of the output terminals of the second horizontal hall element hh2 is connected with the non-inverting input terminal of the operational amplifier A3, so that the other terminal of the second horizontal hall element hh2 is connected with the non-inverting input terminal of the operational amplifier A4.

The inverting input terminal of the operational amplifier A3 is connected with the resistors R4 and R5, so that the inverting input terminal of the operational amplifier A4 is connected with the resistor R4 and R6.

The output terminal of the operational amplifier A3 is connected with the resistor R5 and the resistor R11 in the circuit 454. The output terminal of the operational amplifier A4 is connected with the resistor R6 and the resistor R13 in the circuit 454.

The circuit 453 has a resistor R7, a resistor R8, a resistor R9, a resistor R10, and an operational amplifier A5. The operational amplifier A5 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A5 is connected with the resistors R7 and R8. The non-inverting input terminal of the operational amplifier A5 is connected with the resistors R9 and R10. The output terminal of the operational amplifier A5 is connected with the resistor R8 and the resistor R15 in the circuit 455. The first horizontal potential-difference x1 is output from the output terminal of the operational amplifier A5. One of the terminals of the resistor R10 is connected with the power supply whose voltage is the reference voltage Vref.

The circuit 454 has a resistor R11, a resistor R12, a resistor R13, a resistor R14, and an operational amplifier A6. The operational amplifier A6 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A6 is connected with the resistors R11 and R12. The non-inverting input terminal of the operational amplifier A6 is connected with the resistors R13 and R14. The output terminal of the operational amplifier A6 is connected with the resistor R12 and the resistor R17 in the circuit 455. The second horizontal potential-difference x2 is output from the output terminal of the operational amplifier A6. One of the terminals of the resistor R14 is connected with the power supply whose voltage is the reference voltage Vref.

The circuit 455 has a resistor R15, a resistor R16, a resistor R17, a resistor R18, and an operational amplifier A7. The operational amplifier A7 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A7 is connected with the resistors R15 and R16. The non-inverting input terminal of the operational amplifier A7 is connected with the resistors R17 and R18. The output terminal of the operational amplifier A7 is connected with the resistor R16. The first detected-position signal px, obtained by multiplying a predetermined amplification rate by the difference between the first horizontal potential-difference x1 and the second horizontal potential-difference x2, is output from the output terminal of the operational amplifier A7. One of the terminals of the resistor R18 is connected with the power supply whose voltage is the reference voltage Vref.

The values of the resistors R1 and R4 are the same. The values of the resistors R2, R3, R5, and R6 are the same. The values of the resistors R7˜R14 are the same. The values of the resistors R15 and R17 are the same. The values of the resistors R16 and R18 are the same.

This predetermined amplification rate is based on the values of the resistors R15˜R18.

The operational amplifiers A1˜A4 are the same type of amplifier. The operational amplifiers A5 and A6 are the same type of amplifier.

The circuit 456 has a resistor R19 and an operational amplifier A8. The operational amplifier A8 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A8 is connected with the resistor R19 and one of the input terminals of the second horizontal hall element hh2. The potential of the non-inverting input terminal of the operational amplifier A8 is set at voltage Vfx corresponding to the value of the current which passes through the input terminals of the first and second horizontal hall elements hh1 and hh2. The output terminal of the operational amplifier A8 is connected with the one of the input terminals of the first horizontal hall element hh1. The input terminal of the first horizontal hall element hh1 and the input terminal of the second horizontal hall element hh2 are connected in series. One of the terminals of the resistor R19 is grounded.

Both output terminals of the first vertical hall element hv1 are connected with the circuit 461, so that the circuit 461 is connected with the circuit 463.

Both output terminals of the second vertical hall element hv2 are connected with the circuit 462, so that the circuit 462 is connected with the circuit 464.

The circuits 463 and 464 are connected with the circuit 465.

The circuit 461 is a differential amplifier circuit which amplifies the signal difference between the output terminals of the first vertical hall element hv1, so that the circuit 462 is a differential amplifier circuit which amplifies the signal difference between the output terminals of the second vertical hall element hv2.

The circuit 463 is a subtracting circuit which calculates the first vertical potential-difference y1 on the basis of the difference between the amplified signal difference from the circuit 461 and the reference voltage Vref.

The circuit 464 is a subtracting circuit which calculates the second vertical potential-difference y2 on the basis of the difference between the amplified signal difference from the circuit 462 and the reference voltage Vref.

The circuit 465 is a subtracting circuit which calculates the second detected-position signal py by multiplying a predetermined amplification rate by the difference between the first vertical potential-difference y1 and the second vertical potential-difference y2.

The circuit 461 has a resistor R21, a resistor R22, a resistor R23, an operational amplifier A21, and an operational amplifier A22. The operational amplifier A21 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The operational amplifier A22 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

One of the output terminals of the first vertical hall element hv1 is connected with the non-inverting input terminal of the operational amplifier A21, so that the other terminal of the first vertical hall element hv1 is connected with the non-inverting input terminal of the operational amplifier A22.

The inverting input terminal of the operational amplifier A21 is connected with the resistors R21 and R22, so that the inverting input terminal of the operational amplifier A22 is connected with the resistors R21 and R23.

The output terminal of the operational amplifier A21 is connected with the resistor R22 and the resistor R27 in the circuit 463. The output terminal of the operational amplifier A22 is connected with the resistor R23 and the resistor R29 in the circuit 463.

The circuit 462 has a resistor R24, a resistor R25, a resistor R26, an operational amplifier A23, and an operational amplifier A24. The operational amplifier A23 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The operational amplifier A24 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

One of the output terminals of the second vertical hall element hv2 is connected with the non-inverting input terminal of the operational amplifier A23, so that the other terminal of the second vertical hall element hv2 is connected with the non-inverting input terminal of the operational amplifier A24.

The inverting input terminal of the operational amplifier A23 is connected with the resistors R24 and R25, so that the inverting input terminal of the operational amplifier A24 is connected with the resistor R24 and R26.

The output terminal of the operational amplifier A23 is connected with the resistor R25 and the resistor R31 in the circuit 464. The output terminal of the operational amplifier A24 is connected with the resistor R26 and the resistor R33 in the circuit 464.

The circuit 463 has a resistor R27, a resistor R28, a resistor R29, a resistor R30, and an operational amplifier A25. The operational amplifier A25 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A25 is connected with the resistors R27 and R28. The non-inverting input terminal of the operational amplifier A25 is connected with the resistors R29 and R30. The output terminal of the operational amplifier A25 is connected with the resistor R28 and the resistor R35 in the circuit 465. The first vertical potential-difference y1 is output from the output terminal of the operational amplifier A25. One of the terminals of the resistor R30 is connected with the power supply whose voltage is the reference voltage Vref.

The circuit 464 has a resistor R31, a resistor R32, a resistor R33, a resistor R34, and an operational amplifier A26. The operational amplifier A26 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A26 is connected with the resistors R31 and R32. The non-inverting input terminal of the operational amplifier A26 is connected with the resistors R33 and R34. The output terminal of the operational amplifier A26 is connected with the resistor R32 and the resistor R37 in the circuit 465. The second vertical potential-difference y2 is output from the output terminal of the operational amplifier A26. One of the terminals of the resistor R34 is connected with the power supply whose voltage is the reference voltage Vref.

The circuit 465 has a resistor R35, a resistor R36, a resistor R37, a resistor R38, and an operational amplifier A27. The operational amplifier A27 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A27 is connected with the resistors R35 and R36. The non-inverting input terminal of the operational amplifier A27 is connected with the resistors R37 and R38. The output terminal of the operational amplifier A27 is connected with the resistor R36. The second detected-position signal py, obtained by multiplying a predetermined amplification rate by the difference between the first vertical potential-difference y1 and the second vertical potential-difference y2, is output from the output terminal of the operational amplifier A27. One of the terminals of the resistor R38 is connected with the power supply whose voltage is the reference voltage Vref.

The values of the resistors R21 and R24 are the same. The values of the resistors R22, R23, R25, and R26 are the same. The values of the resistors R27˜R34 are the same. The values of the resistors R35 and R37 are the same. The values of the resistors R36 and R38 are the same.

This predetermined amplification rate is based on the values of the resistors R35˜R38.

The operational amplifiers A21˜A24 are the same type of amplifier. The operational amplifiers A25 and A26 are the same type of amplifier.

The circuit 466 has a resistor R39 and an operational amplifier A28. The operational amplifier A28 has an inverting input terminal, a non-inverting input terminal, and an output terminal.

The inverting input terminal of the operational amplifier A28 is connected with the resistor R39 and one of the input terminals of the second vertical hall element hv2. The potential of the non-inverting input terminal of the operational amplifier A28 is set at voltage Vfy corresponding to the value of the current which passes through the input terminals of the first and second vertical hall elements hv1 and hv2. The output terminal of the operational amplifier A28 is connected with the one of the input terminals of the first vertical hall element hv1. The input terminal of the first vertical hall element hv1 and the input terminal of the second vertical hall element hv2 are connected in series. One of the terminals of the resistor R39 is grounded.

When the magnetic-field generating apparatus of the magnetic-field generating unit 41 a is made of a permanent magnet, the magnetic-field between the permanent magnet (for detecting position) and the hall element unit 44 b exists all the time (see FIG. 10). In FIG. 10, a line of magnetic force is depicted by a dotted line.

An attracting force (the line (1) in FIG. 10), which is based on the magnetic-field, exists. When the movable unit 30 a is driven for moving in the first direction x and the second direction y, this attracting force becomes a resistance force.

For example, when the movable unit 30 a is moved in the second direction y which is depicted by line (2) in FIG. 11, the resistance force pushes back the movable unit 30 a in the opposite direction, and the second direction y which is depictedby the line (3) in FIG. 11. This resistance force prevents movement of the movable unit 30 a, therefore the driving burden is enlarged.

The position-detecting magnetic-field generating unit 41 a in the first embodiment, uses the position-detecting coil 41 a 1 as the magnetic-field generating apparatus. When the position-detecting coil 41 a 1 is electrified, a magnetic-field occurs, so that when the position-detecting coil 41 a 1 is not electrified, a magnetic-field does not occur. The position-detecting coil 41 a 1 is electrified when detecting the position of the movable unit 30 a, so that the position-detecting coil 41 a 1 is not electrified at any time other than that for the detecting operation for detecting the position of the movable unit 30 a, for example during moving the movable unit 30 a etc.

Accordingly, when the movable unit 30 a is moved, an attracting force based on the magnetic-field does not occur (see FIG. 12). The dotted line (4) in FIG. 12 shows that the attracting force is not occurring. Therefore, the resistance force based on the attracting force for moving the movable unit 30 a, is reduced.

Next, the flow of the anti-shake operation, which is performed at every predetermined time interval (1 ms) as an interruption process, independently of the other operations, is explained by using the flowchart in FIG. 13.

In step S11, the interruption process for the anti-shake operation is started. In step S12, the first angular velocity vx, which is output from the angular velocity detecting unit 25, is input to the A/D converter A/D 0 of the CPU 21 and is converted to a digital signal. The second angular velocity vy, which is output from the angular velocity detecting unit 25, is input to the A/D converter A/D 1 of the CPU 21 and is converted to a digital signal.

In step S13, the on state signal is output from the port P50 of the CPU 21 to the second driver circuit 48, so that driving the position-detecting coil 41 a 1 is started.

In step S14, the position of the movable unit 30 a is detected by the hall element unit 44 b, so that the first detected-position signal px, which is calculated by the hall-element signal-processing circuit 45, is input to the A/D converter A/D 2 of the CPU 21 and is converted to a digital signal, and the second detected-position signal py, which is calculated by the hall-element signal-processing circuit 45, is input to the A/D converter A/D 3 of the CPU 21 and is converted to a digital signal.

Therefore, the present position of the movable unit 30 a P (pdx, pdy) is determined. In step S15, the off state signal is output from the port P50 of the CPU 21 to the second driver circuit 48, so that driving the position-detecting coil 41 a 1 is stopped.

In step S16, it is judged whether the value of the IS is 0. When it is judged that the value of the IS is 0 (IS=0), in other words in the non anti-shake mode, the position S (sx, sy) of the movable unit 30 a (the imaging unit 39 a), which should be moved, is set to the center of its movement range, in step S17. When it is judged that the value of the IS is not 0 (IS=1), in other words in the anti-shake mode, the position S (sx, sy) of the movable unit 30 a (the imaging unit 39 a), which should be moved, is calculated on the basis of the first and second angular velocities vx and vy, in step S18.

In step S19, the driving force D, which drives the first driver circuit 29 in order to move the movable unit 30 a to the position S, in other words the first PWM duty dx and the second PWM duty dy, is calculated on the basis of the position S (sx, sy), which is determined in step S17 or step S18, and the present position P (pdx, pdy).

In step S20, the first driving coil 31 a is driven by using the first PWM duty dx through the first driver circuit 29, and the second driving coil 32 a is driven by using the second PWM duty dy through the first driver circuit 29, so that the movable unit 30 a is moved.

The process in steps S19 and S20 is an automatic control calculation, which is used with the PID automatic control for performing general (normal) proportional, integral, and differential calculations.

Next, the second embodiment is explained. In the second embodiment, the position-detecting magnetic-field generating unit 41 a has a magnetic core 41 a 2 (see FIG. 14). The position-detecting coil 41 a 1 is wound around a magnetic core 41 a 2. The magnetic core 41 a 2 is made of a magnetic material such as iron etc.

The magnetic core 41 a 2 has a rectangular prism form (a cuboid). The rectangular prism form has a front-surface which faces the hall element unit 44 b. The front-surface is a square shape which is the same as the outer circumference of the position-detecting coil 41 a 1, viewed from the third direction z.

The other constructions of the photographing apparatus 1 in the second embodiment are the same as those in the first embodiment.

A condition where magnetic-flux passes through the magnetic core 41 a 2 is better than that through the air, in other words the relative magnetic permeability of the magnetic core 41 a 2 is larger than that with air. Accordingly, when the magnetic core 41 a 2 is used in the position-detecting magnetic-field generating unit 41 a, the inductance of the position-detecting coil 41 a 1 is increased, and the magnetic-flux density between the position-detecting magnetic-field generating unit 41 a and the hall element unit 44 b is increased, and then the accuracy of the position-detecting is improved in comparison with when the magnetic core 41 a 2 is not used in the position-detecting magnetic-field generating unit 41 a like in the first embodiment.

Next, the third embodiment is explained. In the third embodiment, the position-detecting coil 41 a 1 forms a seat and a spiral shape coil pattern (see FIG. 15).

The other constructions of the photographing apparatus 1 in the third embodiment are the same as those in the first embodiment.

The thickness of the position-detecting coil 41 a 1, which is the seat coil in the third embodiment, in the third direction z, is very small. Accordingly, the position-detecting coil 41 a 1 can be attached to the movable circuit board 49 a without greatly increasing thickness, so that the space between the movable circuit board 49 a and the hall element unit 44 b can be short in comparison with that in the first embodiment. Therefore, the anti-shake apparatus 30 can be downsized. Further, a plurality of seat coils, which compose the position-detecting coil 41 a 1, can be layered.

It is explained that the hall element unit 44 b is a two-axes hall element which has two hall elements for detecting the first location in the first direction x of the movable unit 30 a and two hall elements for detecting the second location in the second direction y of the movable unit 30 a. However, the hall element unit 44 b may be a one-axis hall element which has a hall element for detecting the first location in the first direction x of the movable unit 30 a and a hall element for detecting the second location in the second direction y of the movable unit 30 a.

The position-detecting operation is performed on the basis of the difference of the potential-differences between output terminals of the hall elements, when the two-axes hall element is used. The position-detecting operation is performed on the basis of the potential-differences between output terminals of the hall elements, when the one-axis hall element is used. Accordingly, when the one-axis hall element is used for detecting the position, the construction of the anti-shake apparatus can be simplified in comparison with when the two-axes hall element is used.

Further, it is explained that the movable unit 30 a has the imaging device 39 a 1. However, the movable unit 30 a may have a hand-shake correcting lens instead of the imaging device.

Further, it is explained that the hall element is used for position-detecting as the magnetic-field change-detecting element, however, another detecting element may be used for position-detecting. Specifically, the detecting element may be an MI (Magnetic Impedance) sensor, in other words a high-frequency carrier-type magnetic-field sensor, or a magnetic resonance-type magnetic-field detecting element, or an MR (Magneto-Resistance effect) element. When one of the MI sensor, the magnetic resonance-type magnetic-field detecting element, and the MR element is used, the information regarding the position of the movable unit can be obtained by detecting the magnetic-field change, similar to using the hall element.

Although the embodiments of the present invention have been described herein with reference to the accompanying drawings, obviously many modifications and changes may be made by those skilled in this art without departing from the scope of the invention.

The present disclosure relates to subject matter contained in Japanese Patent Application No. 2004-023710 (filed on Jan. 30, 2004), which is expressly incorporated herein by reference, in its entirety.

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Classifications
U.S. Classification348/208.99, 348/E05.028, 348/E05.046
International ClassificationH04N5/225, H04N5/228, H04N5/232
Cooperative ClassificationH04N5/23287, H04N5/23248, H04N5/2254
European ClassificationH04N5/232S2C2, H04N5/225C4, H04N5/232S
Legal Events
DateCodeEventDescription
Jan 28, 2005ASAssignment
Owner name: PENTAX CORPORATION, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:UENAKA, YUKIO;SEO, SHUZO;REEL/FRAME:016235/0917
Effective date: 20050124